Effect of hot air drying on the polyphenol profile of Hongjv ( Citrus reticulata Blanco, CV. Hongjv) peel: A multivariate analysis

Abstract

Hongjv peel (HP), a spice rich in polyphenols, is generally dried for its preservation. Hot air drying (HAD) at 50°C, 60°C, 70°C, and 80°C was performed in this study to dehydrate HP and it was found that the drying rate increased in line with the increase of HAD temperature. Absorbance analysis showed that HAD induced significant decreases in the total polyphenol content (TPC), total flavonoid content (TFC), and antioxidant activity of HP. Ultra performance liquid chromatography‐tandem mass spectrometry (UHPLC‐MS/MS) analysis found 18 phytochemicals in the HP, including 11 flavonoids, 6 phenolic acids, and 1 triterpenoid, while multivariate analysis revealed that chlorogenic acid, hesperidin, naringenin, and phloretin in the HP were influenced mainly by HAD. HAD‐induced degradations were non‐spontaneous, endothermic reactions, consistent with the first‐order reaction kinetics. In addition, the results suggest that HAD is more likely to degrade polyphenols that include an ester bond or glucoside. Practical applications Among the various methods of preservation used to process spices, HAD is still the most effective. The polyphenol of HP possesses numerous health benefits, including being anti‐oxidative, anti‐inflammatory, anticancer, antiproliferative, and other qualities. This study provides a method through which to obtain insight into the effects of HAD on polyphenols in food, and indicates potential targets to increase the polyphenol content in HP.

Effects of Different Drying Methods and Temperature on the Drying Behavior and Quality Attributes of Cherry Laurel Fruit

“…It can be explained that higher temperatures reduced the drying time e.g., in HAD, it was 1980 min while the temperature was 50 • C, and 770 min while it was 70 • C, meaning that the samples were subjected to less heat treatment during the whole drying process. Moreover, the rise in the temperature could damage the food structure, and bioactive compounds bound to the matrix could be better released into the extraction medium [25]. It was also known that higher temperatures could denature the polyphenol oxidase enzyme that is responsible for the degradation of phenolic compounds, therefore would increase their retention [26].…”

Air-impingement jet drying at high temperature and air velocity enhanced the dehydration efficiency, quercetin content, and antiradical properties of fig slices

“…The antiradical properties of the polyphenol extracts were assessed based on the DPPH• and ABTS •+ scavenging activities (Li et al, 2020a;2020b). The DPPH• scavenging activity was assessed following a previously modified method (Blois, 1958), while the ABTS •+ scavenging activity was measured following the method reported by Re et al (1999).…”

Grape Infusions: Between Nutraceutical and Green Chemistry

“…Natural solar drying, or, when the sun is not available, hot-air drying is the most used method to produce dried enological and agricultural products due to the smaller operating cost. However, phenolic, and other nutraceutical compounds, that can be extracted from these biological wastes are heat-sensitive substances [114], therefore temperatures lower than 60-70 • C are considered suitable for the pre-treatment of grape marc and other agricultural by-products to retain its bioactive compounds [24,115].…”